Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Özdemir, Akın(10)
- Kutlu, Naciye(9)
- Uçurum, Metin(7)
- Dertli, Enes(6)
- Tozlu, Alperen(5)
- Şahin, Engin(5)
- Serencam, Hüseyin(4)
- Teke, Çağatay(4)
- Özahi, Emrah(4)
- Bayram, Sinan(3)
- Ecem Bayram, Nesrin(3)
- Gerçek, Yusuf Can(3)
- Kamiloglu, Aybike(3)
- Kamiloğlu, Aybike(3)
- Ozdemir, Akin(3)
- Tayfur, Bilal(3)
- Yilmaz, Mustafa Tahsin(3)
- Çelik, Saffet(3)
- Abdioglu, Murat(2)
- Abuşoğlu, Ayşegül(2)
- Can, Zehra(2)
- Daloğlu, Ayşe T.(2)
- Kara, Yakup(2)
- Karaali, Rabi(2)
- Muslu, Asli(2)
- Ozkat, Erkan Caner(2)
- Ozturk, U. Kemal(2)
- Abca, Tuğba Elbir(1)
- Aksuoğlu, Selmani(1)
- Alamoudi, Mohammed(1)
- Alidrisi, Hassan M.(1)
- Altuncu, Fatma Kübra(1)
- Arici, M.(1)
- Arslantürk, Cihat(1)
- Açikyildiz, Metin(1)
- Baluken, Pınar(1)
- Baslar, Mehmet(1)
- Bayram, Nesrin Ecem(1)
- Baştürk, Fatma Nur(1)
- Bekar, Fevzi(1)
Yayınlar
- MakaleAçık Erişim2018Scopus SJRQ1Thermoeconomic multi-objective optimization of an organic Rankine cycle (ORC) adapted to an existing solid waste power plant
Özahi, Emrah; Tozlu, Alperen; Abuşoğlu, Ayşegül
In this paper, thermodynamic and thermoeconomic analyses, and also optimization of an organic Rankine cycle (ORC) were performed. The system was adapted to an existing solid waste power plant with a 5.66 MW installed power capacity in order to produce additional power from the exhaust gas. The actual operating data of the plant were utilized during all stages of the analyses. The originality of this paper is based on the analysis of the possibility of the energy conversion of an exhaust gas with a temperature of 566 & #x000B0;C into the electricity by utilizing an ORC system in the concept of waste-to-energy. Four different working fluids: toluene, octamethyltrisiloxane (MDM), octamethyl cyclotetrasiloxane (D4) and n-decane were considered and analyzed for the current system. This is also another novelty of this study due to lack of such a study, in the open literature, that deals with an ORC utilized for a typical municipal solid waste power plant. According to the thermoeconomic analyses, toluene was found to be the optimum working fluid with the maximum power output of 584.6 kW and the exergy efficiency of 15.69%. The optimization of the cycle was performed by using the non-dominated sorting genetic algorithm method (NSGA-II) in MATLAB software environment. The optimization results were compared and the deviations of the net power output and the total cost rate were evaluated as & #x2212;5.89%, & #x2212;3.51 & #x00024;/h for toluene; 0.96%, & #x2212;3.60 & #x00024;/h for MDM; 8.45%, & #x2212;2.04 & #x00024;/h for D4 and 2.00%, & #x2212;5.54 & #x00024;/h for n-decane, respectively.
AtıfScopus87WoS80OpenAlex88
İncele - MakaleAçık Erişim2018Scopus SJRQ1Optimization of reactive powder concrete by means of barite aggregate for both neutrons and gamma rays
Gökçe, H. Süleyman; Yalçınkaya, Çağlar; Tuyan, Murat
High performance concrete has been often preferred in special engineering structures and in challenging composites products. Researchers have recently focused on the radiation shielding characteristics of these type concrete mixtures due to rising nuclear industry in the developing world. In the study, performance of reactive powder concrete was researched with regard to gamma-ray and neutron attenuation when its normal weight aggregate replaced with heavyweight aggregate (barite). For this purpose, reactive powder concrete mixtures were prepared 100% quartz aggregate, 100% barite aggregate and their blending 50–50%, by volume. Some physical and mechanical characteristics such as density, compressive strength, fracture energy, flexural strength and modulus of elasticity of the mixtures were determined. Gamma-ray attenuation coefficients and transmission thickness values were theoretically established for commonly known gamma energies (661.7, 1173.2 and 1332.5 keV). Optimization of the reactive powder mixtures was performed for both neutron and gamma-ray attenuation at 8 MeV. As a result, barite significantly increased the gamma-ray attenuation coefficients of reactive powder concrete. The mechanical performance of reactive powder concrete, however, was markedly reduced as a result of barite substitution. Replacement of quartz by barite aggregate has a more adverse impact on flexural strength than that of compressive strength. A mix that contains 40% barite aggregate of total aggregate volume was found as an optimum RPC mixture for simultaneously shielding neutrons and gamma rays.
AtıfScopus138WoS126OpenAlex141İncele - MakaleYayıncıda açık erişim2018Scopus SJRQ2Optimization of Adsorption Parameters for Ultra-Fine Calcite Using a Box-Behnken Experimental Design
Uçurum, Metin; Özdemir, Akln; Teke, Çaǧatay; Serencam, Hüseyin; Ipek, Mümtaz
Removal of heavy metals from wastewater is a significant issue because it prevents environmental-based concerns and impacts a large number of diseases and disorders. Many low-cost natural materials have been offered recently as possible precursors to commercial synthetic adsorbents. Ultra-fine calcite, one of these natural materials, has been investigated as a potential commercial adsorbent. Response surface designs are effective experimental techniques to investigate the heavy metal adsorption capacity of ultra-fine calcite. In the present study, one such response surface design, Box-Behnken, is used in order to optimize adsorption factors, such as pH level, initial metal concentration, stirring rate and adsorption time, and to determine the heavy metal capacity of this adsorbent. Our results show that the proposed methodology is an effective approach to optimizing the adsorption process and to maximize the heavy metal capacity.
AtıfScopus9WoS7OpenAlex12İncele - BildiriYalnız künye2018A perspective of a dual response surface model with a desirability function
Ozdemir, Akin; Turkoz, Mehmet
The use of response surface analysis is an effective method to improve the quality of products and processes. Along the same line, a dual response surface-based robust parameter design model may reduce product or process variability by selecting levels of input variables. In many products and processes, the researchers and practitioners may need to deal with a desirable response. Therefore, this paper proposes a new dual response surface model-based robust parameter design model with a desirability function to obtain a set of optimal operating conditions for multiple responses while minimizing the product or process variation as possible as. The proposed methodology is efficient and it improves the quality of the products by decreasing the variability in the process. The comparative studies show that proposed method is effective and outperforms the existing procedures.
AtıfScopus1İncele - MakaleYalnız künye2018Scopus SJRQ1Thermoeconomic analysis and optimization of a Re-compression supercritical CO2 cycle using waste heat of Gaziantep Municipal Solid Waste Power Plant
Tozlu, Alperen; Abuşoğlu, Ayşegül; Özahi, Emrah
This paper presents thermodynamic and thermoeconomic analyses as well as optimization of a re-compression supercritical CO2 cycle. A gas turbine cycle (GT) is adapted as a model to an existing plant to generate additional power in Gaziantep Municipal Solid Waste Power Plant (GMSWPP). The total capital cost rate and total cost rate of the GT cycle are found to be 20.47 $/h and 77.14 $/h, respectively utilizing SPECO by using the exhaust gas of 16 kg/s with 1.9 bar and 566.7 °c. The net power, the energy and exergy efficiencies, the total cost and the total capital cost rates of the GT cycle are optimized by +1.73%, +3.21%, +2.45%, −1.11% and −1.64%, respectively using NSGA-II in MATLAB in the range of 2.5≤PR≤4, 200≤P6≤216, 16≤T0≤23 and 9.1≤LMTD≤12.9. This paper provides an originality such that optimization as well as thermodynamic and thermoeconomic analyses is performed simultaneously for an existing MSW power plant, which can be stressed that there are scarce amounts of studies related on this field. Moreover, as another novelty, it can be emphasized that net power output of such like plants which have similar capacity can be improved using the developed model and NSGA-II optimization method.
AtıfScopus47WoS43OpenAlex48İncele - MakaleYalnız künye2017Optimization of Pectin Extraction from Orange Pulp and Characterization of Compositional and Steady Shear Properties
Yilmaz, Mustafa Tahsin; Muslu, Asli; Karasu, Salih; Bozkurt, Fatih; Dertli, Enes
Pectin, which is one of the most important wastes of fruit juice industry, was extracted from orange pulp at optimum conditions (pH, time and temperature) and modified using pectinase. The effect of modification on the structural properties of pectin was monitored using Fourier transformed infrared spectroscopy (FTIR) and high performance liquid chromatography (HPLC) analyses. The bands at 1600-1800 cm(-1) which indicate the specific region and quality of pectin were detected using FTIR while galacturonic acid content was determined using HPLC. The results showed that the galacturonic acid content of pectin from orange pulp was determined to be 406.44 mg/g powder pectin while that of the modified pectin from the orange pulp was determined to be 465,34 mg/g powder pectin. In addition, flow properties of the pectin samples were determined using rheological analysis. The viscosity and viscoelastic properties of the modified pectin samples were revealed to be different from those of non-modified pectin samples. The consistency index values of unmodified and modified pectin samples were determined to be 0.0559 Pa.s(n) and 0.0046 Pa.s(n), respectively.
AtıfWoS3İncele - MakaleAçık Erişim2017Scopus SJRQ2Taguchi Approach for Optimization of Parameters that Effect Grain Size of Cast A357 Alloy
Çolak, M.; Dlşplnar, D.
Grain refining and modification are common foundry practice for improving properties of cast Al-Si alloys. In general, these types of treatments provide better fluidity, decreased porosity, higher yield strength and ductility. However, in practice, there are still some discrepancies on the reproducibility of the results from grain refining and effect of the refiner's additions. Several factors include the fading effect of grain refinement and modifiers, inhomogeneous dendritic structure and non-uniform eutectic modification. In this study, standard ALCAN test was used by considering Taguchi's experimental design techniques to evaluate grain refinement and modification efficiency. The effects of five casting parameters on the grain size have been investigated for A357 casting alloy. The results showed that the addition of the grain refiner was the most effective factor on the grain size. It was found that holding time, casting temperature, alloy type and modification with Sr were less effective over grain refinement.
AtıfScopus7WoS6OpenAlex7İncele - MakaleYalnız künye2016Rheological and Molecular Characterization of Modified Pectin from Sugar Beet Meal
Yilmaz, Mustafa Tahsin; Muslu, Asli; Dertli, Enes; Toker, Omer Said
The pectin was produced from sugar beet pulp, one of the significant waste of sugar industry, at optimum conditions (pH, time and temperature). Then, the modification was carried out using pectinase. FT-IR (Fourier transform infrared spectroscopy) and HPLC (high performance liquid chromatography) analysis were performed to characterize the differences between modified and unmodified pectin. FT -IR analysis revealed the specific regions of pectin and 1600-1800 cm-1 bands. Galacturonic acid content was analyzed by HPLC. The obtained results revealed that the modified pectin had higher galacturonic acid content. In addition, flow properties of the modified pectin was also determined. The flow characteristics of modified pectin was observed to change.
AtıfWoS1İncele - MakaleYalnız künye2016Scopus SJRQ3Thermodynamic optimization of a zero CO2 emission cogeneration cycle
Karaali, Rabi; Ozturk, Ilhan Tekin
CO2 emissions that have the greatest negative impact on the greenhouse and the global warming that should be decreased or kept at the same rates. Today fossil fuels share 60 % of total electricity production of the world, which plays an important role on CO2 emissions. Thermal cogeneration and zero CO2 emission cycles have potential for reducing this effect. By taking into consideration the most applicable and important zero CO2 emission cycles, a new cycle is designed. Thermodynamic analyses and optimization of this cycle is studied with FORTRAN code. The optimization results of this cycle show that the maximum exergy efficiency of this new cycle is 64 %, which is 17.6 % higher than (0,544) the one for the air preheated cogeneration cycle (APHCC) and 18.7 % higher than (53,9) the absorption cooling zero CO2 emission cycle (ACZEC). In the introduced new cycle, steam and CO2 in the exhaust gases are condensed so that the condensing energy of them is regained. For that reason, the heat output and the electrical power of the introduced cycle is better than the other cogeneration cycles.
AtıfScopus3İncele - MakaleAçık Erişim2016Scopus SJRQ1Development of a fermented ice-cream as influenced by in situ exopolysaccharide production: Rheological, molecular, microstructural and sensory characterization
Dertli, Enes; Toker, Omer S.; Durak, M. Zeki; Yilmaz, Mustafa T.; Tatlisu, Nevruz Berna; Sagdic, Osman; Cankurt, Hasan
This study aimed to investigate the role of in situ exopolysaccharide (EPS) production by EPS+ Streptococcus thermophilus strains on physicochemical, rheological, molecular, microstructural and sensory properties of ice cream in order to develop a fermented and consequently functional ice-cream in which no stabilizers would be required in ice-cream production. For this purpose, the effect of EPS producing strains (control, strain 1, strain 2 and mixture) and fermentation conditions (fermentation temperature; 32, 37 and 42°C and time; 2, 3 and 4 h) on pH, S. thermophilus count, EPS amount, consistency coefficient (K), and apparent viscosity (η50) were investigated and optimized using single and multiple response optimization tools of response surface methodology. Optimization analyses indicated that functional ice-cream should be fermented with strain 1 or strain mixture at 40-42°C for 4 h in order to produce the most viscous ice-cream with maximum EPS content. Optimization analysis results also revealed that strain specific conditions appeared to be more effective factor on in situ EPS production amount, K and η50 parameters than did fermentation temperature and time. The rheological analysis of the ice-cream produced by EPS+ strains revealed its high viscous and pseudoplastic non-Newtonian fluid behavior, which demonstrates potential of S. thermophilus EPS as thickening and gelling agent in dairy industry. FTIR analysis proved that the EPS in ice-cream corresponded to a typical EPS, as revealed by the presence of carboxyl, hydroxyl and amide groups with additional α-glycosidic linkages. SEM studies demonstrated that it had a web-like compact microstructure with pores in ice-cream, revealing its application possibility in dairy products to improve their rheological properties.
AtıfScopus86WoS74OpenAlex98
İncele - MakaleAçık Erişim2016Scopus SJRQ3Investigation of the cyanide leaching optimization for ultrafine grinding gold–silver ore
Birol, Onur; Uçurum, Metin
In recent years, the ultrafine grinding (UFG) process has become increasingly important for the recovery of precious metals (especially for Au and Ag) from raw ores. It is well known that cyanide leaching of gold–silver ore has been an accepted process in the world. In the current study, UFG was proposed as a pretreatment method prior to cyanide leaching of a gold–silver ore. First, the ore was crushed and ground by jaw, cone crusher, and ring mill, respectively. Particle size of ground product was 75 µm based d80. Second, the fine product was subjected to the grinding process by vertical wet stirred ball mill, and the final ultrafine product was used as leach feed material. The leach feed material had about d80 = 20 µm and d50 = 6.02 µm particle size. Some important leaching parameters were optimized by using the ultrafine powder in the study. The final leach experiments demonstrated that the recoveries of Au and Ag were 91.92% and 82.15% under optimum leaching conditions such as 150 kg/t quicklime dosage, 25% pulp density, 85°C leach temperature, 500 g/t cyanide concentration, and 90 h leaching time.
AtıfScopus11WoS10OpenAlex11İncele - MakaleYalnız künye2015Scopus SJRQ1Thermoeconomic optimization of gas turbine cogeneration plants
Karaali, Rabi; Öztürk, Ilhan Tekin
In this study, a novel thermoeconomic optimization method that is simple and efficient, for real complex cycles is introduced. First, a thermoeconomic analysis method that is called non-linear simplex direct search method is improved for the purposes of this study. The objective of this paper is to apply this method to four cogeneration cycles that are simple cycle, inlet air cooling cycle, air preheated and air-fuel preheated cycles for analyzing and optimizing. The four cycles are thermoeconomically optimized for constant power and steam mass (30 MW and 14 kg/s saturated steam flow rate at 2000 kPa), for constant power (30 MW) and for variable steam mass, and for variable power and steam mass by using the cost equation method and the effect of size on equipment method. The results obtained by the effect of size on equipment and by the cost equations methods are very different from each other. For the case of global optimization, the optimum electricity costs which also correspond to minimum are obtained as 0,0432 $/kWh for simple cycle, 0,0514 $/kWh for inlet air cooling cycle 0,0577 $/kWh for air preheated cycle and 0,058 $/kWh for air-fuel preheated cycle by using cost equations method. (C) 2014 Elsevier Ltd. All rights reserved.
AtıfWoS32OpenAlex39İncele - MakaleAçık Erişim2015Scopus SJRQ1Effect of in situ exopolysaccharide production on physicochemical, rheological, sensory, and microstructural properties of the yogurt drink ayran: An optimization study based on fermentation kinetics
Yilmaz, M.T.; Dertli, E.; Toker, O.S.; Tatlisu, N.B.; Sagdic, O.; Arici, M.
Exopolysaccharide (EPS)-producing starter cultures are preferred for the manufacture of fermented milk products to improve rheological and technological properties. However, no clear correlation exists between EPS production and the rheological and technological properties of fermented milk products such as the yogurt drink ayran. In this study, 4 different strain conditions (EPS- and EPS+ Streptococcus thermophilus strains) were tested as a function of incubation temperature (32, 37, or 42°C) and time (2, 3, or 4 h) to determine the effect of culture type and in situ EPS production on physicochemical, rheological, sensory, and microstructural properties of ayran. Furthermore, we assessed the effect of fermentation conditions on amounts of EPS production by different EPS-producing strains during ayran production. A multifactorial design of response surface methodology was used to model linear, interaction, and quadratic effects of these variables on steady shear rheological properties of ayran samples and in situ EPS production levels. The physicochemical and microbiological characteristics of ayran samples altered depending on incubation conditions and strain selection. Steady shear tests showed that ayran samples inoculated with EPS+ strains exhibited pseudoplastic flow behavior. Production of ayran with EPS- strain (control sample) resulted in the lowest apparent viscosity values (η50), whereas those produced with the combination of 2 EPS+ strains yielded ayran with notably increased η50 values. We concluded that incubation time was the variable with the greatest effect on η50, consistency coefficient (K), and flow behavior index (n) values. In situ EPS production was also affected by these conditions during ayran fermentation in which strain-specific metabolism conditions were found to be the most important factor for EPS production. In addition, these findings correlated the amount of in situ EPS produced with the rheological properties of ayran. Scanning electron microscopy images of the samples showed differences in structural features, revealing a prominent network strand structure in the ayran samples inoculated with the admixture of 2 EPS-producing strains incubated at 37°C for 3 h. These results provide useful information for large-scale production of ayran by the dairy industry.
AtıfScopus79WoS65OpenAlex92İncele - BildiriYalnız künye2012Scopus SJRQ3Optimization of process parameters for removal of Cr(VI) by Hypnum cupressiforme using response surface methodology (RSM)
Özkan, Esra; Gürses, Ahmet; Açikyildiz, Metin; Güneş, Kübra
Response surface methodology was applied to optimize the removal of chromium ion by Hypnum cupressiforme from an aqueous solution. Experiments were analyzed using response surface methodology (RSM). The biosorption process was investigated as a function of five independent factors, sorption time, sorption temperature, initial ion concentration, sorbent dosage, and mixing rate. The optimum conditions for the chromium biosorption were found to be 760 min, 313K, 30mg/L, 0.01 mg/100mL, 107 min-1 respectively, for sorption time, sorption temperature, initial ion concentration, sorbent dosage, and mixing rate.
AtıfScopus2İncele - MakaleAçık Erişim2012Scopus SJRQ1Effect of ultrasound treatment on steady and dynamic shear properties of glucomannan based salep dispersions: Optimization of amplitude level, sonication time and temperature using response surface methodology
Karaman, Safa; Yilmaz, Mustafa Tahsin; Ertugay, Mustafa Fatih; Baslar, Mehmet; Kayacier, Ahmed
The present study investigated effect of different amplitude levels (40, 70 and 100%), sonication temperatures (40, 50 and 60 °C) and exposure times (3, 7 and 11 min) on steady shear properties; apparent viscosity (η), shear stress (σ), consistency coefficient (K), flow behavior index (n) and dynamic shear properties; storage modulus (G′), loss modulus (G″), complex viscosity (η), complex modulus (G) and loss tangent (tan δ) values of glucomannan based salep solution (SS) and salep drink (SD) samples. In addition, the steady and dynamic shear properties were optimized using ridge analysis in terms of amplitude level, sonication temperature and exposure times levels. Increasing amplitude level and sonication time decreased considerably the η, σ, K, G′, G″ and η values of salep dispersions (SS and SD samples). However, sonication temperature did not have a remarkable effect on these properties.
AtıfScopus40WoS36OpenAlex42İncele - MakaleYalnız künye2011Scopus SJRQ1A Taguchi approach for optimization of design parameters in a tube with coiled wire inserts
Gunes, Sibel; Manay, Eyuphan; Senyigit, Ercan; Ozceyhan, Veysel
This study presents the determination of the optimum values of the design parameters in a tube with equilateral triangular cross-sectioned coiled wire inserts. The effects of the design parameters such as the ratio of the distance between the coiled wire and test tube wall to tube diameter (s/D), pitch ratio (P/D), ratio of the side length of equilateral triangle to tube diameter (a/D) and Reynolds number (Re) on heat transfer and pressure drop were investigated by using Taguchi method. The Nusselt number and friction factor were considered as performance parameters. An L9(34) orthogonal array was chosen as experimental plan. The goal of this study is to reach maximum heat transfer (i.e. Nusselt number) and minimum pressure drop (i.e. friction factor). First of all, each goal was optimized, separately. Then, all the goals were optimized together, considering the priority of the goals. Contribution ratios for each parameter on the heat transfer and pressure drop were determined. Consequently, the optimum results were found to be s/D = 0.0357, P/D = 1, a/D = 0.0714 and Re = 19800.
AtıfScopus115WoS100OpenAlex113İncele